Test hypothesis that hyperglycemia or elevated NEFA levels can induce insulin resistance in non-diabetic subjects and to determine whether the effect of elevated NEFA levels is rapidly reversible when NEFA levels are allowed to fall to normal. Test hypothesis that hyperglycemia leads to a decrease in IR kinase activity in skeletal muscle and that hyperglycemia decreases IR tyrosine kinase activity through enhanced serine or threonine phosphorylation of the IR probably mediated via increased PKC activity.